The specific aims of this study are to measure gastric, small bowel, and colonic transit in 18 healthy volunteers randomized to placebo, 30 ug, or 60 ug, t.i.d. of pramlintide, and to measure gastric emptying in 6 type I diabetics and 6 type II diabetics in response to placebo, 30 ug, or 60 ug, t.i.d. of pramlintide. Our hypotheses is that pramlintide dose dependently retards gastric emptying without altering small bowel or colonic transit in health, 30 ug, t.i.d. (low dose) of pramlintide retards gastric emptying in type I diabetes mellitus, and 60 ug, t.i.d. (high dose) of pramlintide retards gastric emptying in both type I and type II diabetes mellitus.